The present invention relates to a one piece cage for rolling bearings made of a synthetic material having a predetermined configuration providing greater encapsulation of the rollers which results in less "roller sag." The cage is also characterized by novel features of construction and arrangement to minimize the amount of cage flexing and therefore provide maximum roller support and optimum running accuracy.
Cages of this type having radially outwardly extending projections are known in the prior art. Thus this type of cage permits insertion of the rollers into the pockets of the cage from a direction radially outwardly of the cage. Accordingly the cage is limited in its application for bearings wherein the inner ring is provided with rims on at least one or both sides of the inner raceway and the outer ring is rimless. The cage is not suitable for a rimmed outer ring. There are also cages having projections which extend radially inwardly into the cage bore. This cage of course is not suitable for bearings with rims on the inner ring on either side of the raceway.
There are also prior cages made of metal comprising annular members and intermediate webs defining pockets for the rollers. In these cages the webs are spaced apart to permit free insertion of the rollers from a radial direction and then are peened over to form projections thereby fixing the rollers in the pocket. These subsequent peening operations, of course, increase the cost of the cage and the overall assembly.
Other prior art patents which show cages bearing a superficial resemblance to the cage of the present invention but which do not have the structural features and details of the present invention and therefore the functional advantages are as follows: Ryanen U.S. Pat. No. 3,881,790, the annular members are not of a uniform height for their circumference and comprise a series of sections alternatingly offset radially. In order for the cage to be balanced, this construction does not provide the flexibility in terms of the number of pockets and is limited to an even number of pockets. Furthermore, since the annular members or side rings are not continuous over the radial extension of the cage webs, the rollers are not encapsulated to the extent that they are in applicant's cage. Furthermore, as seen in FIG. 4, the relief cut 10 extends inwardly beyond the inner edge of the annular members so that there is more of a tendency for this cage to flex. In summary, with the non-symmetrical design in Ryanen there is a greater possibility of cage flexing and therefore does not provide the same roller support and running accuracy as applicant's cage.
The Pfaffenberger U.S. Pat. No. 3,647,273 shows a cage made of two side rings and a number of separately manufactured webs which are connected to the side rings by swaging over the ends of the webs. This cage does not include flexible projections on the inner and outer edges of the webs. This cage is obviously much more complicated and expensive to manufacture than applicant's cage and does not allow for the assembly flexibility of applicant's cage noted above.
Nisbet U.S. Pat. No. 3,495,889 is also a plural-piece cage requiring the parts to be assembled in a very precise manner or otherwise the running performance of the cage is adversely affected. Furthermore due to the fact that only one part of the cage has deformable projections, the rollers can be snapped in only from one side. The annular members and webs are clearly different from the applicant's symmetrical design providing good encapsulation of the rollers. In a symmetrical arrangement, any number of roller pockets may be provided and the rollers are guided equally and uniformly on both sides of the cage. Applicant's cage, therefore, allows for the maximum number of and size of rollers and therefore the bearing capacity is optimized.
In Bott U.S. Pat. No. 1,765,648, the relief cuts in the cage are extremely deep and extend close to the pitch line of the rolling elements. This construction as noted above results in cage flexing which adversely affects roller support and running accuracy.
The British Pat. No. 1,390,496 and French Pat. No. 993,520 show essentially similar type cages wherein the flexible portions of the webs extend substantially beyond the outer edges of the side pieces. In this construction the rollers are only insertable from outside the cage. Furthermore the flexible portions are unsupported by the side rings. Therefore, cage flexing is inherent which provides inadequate roller support and running accuracy.